Repair Oversized PST Files: Complete Outlook Recovery Guide

All You Need to Know to Repair Oversized Outlook PST 

PST (Personal Storage Table) file clearly stores the Outlook’s entire mailbox data locally. Microsoft has constantly increased PST file limits over the years, but there are still thresholds. The common limits distributed over time are:

• Earlier versions – Outlook 2002 (ANSI PST): 2 GB

• Outlook 2003 -2007 (UNICODE PST): 20 GB

• Outlook 2010 – Current versions (UNICODE PST): 50 GB

Though 50 GB is the max limit for PST supported currently, the performance generally degrades if the file contains large and bulky attachments, too. Thus, you must know how to compress PST file. 

Usual Symptoms of an Oversized PST File 

If you want to fix large PST file, recognizing it is very important. This is only possible when you know what happens when the PST file size limit is exceeded. You may find the following warnings before Outlook completely fails to function:

• Too much time is consumed when starting MS Outlook 
• The system often freezes or crashes 
• Emails are not sent or received in Outlook 
• PST files cannot be synced or opened 
• Outlook shows limit warnings, and items go missing 
• Error messages: Outlook data file has reached the maximum size
• “xyz.pst cannot be accessed: code 0x80040116” and other errors 
• Routine tasks fail to perform, and Error 0x00040820 keeps repeating

How PST File Become Oversized?

Factors mentioned below contribute to the growth of the Outlook data file over time, demanding you repair corrupt oversized Outlook PST files:

• High-resolution images, videos, PDFs, large email attachments, and project files –Storage Out
• Repeated messages, synchronization duplicates, and copied folders- Inflated Mailbox 
• Years of historical data archived altogether in a single PST file – Long Archival
• Using older ANSI PST with 2 GB limits, convert ANSI PST to UNICODE PST– Outdated Format 

Best Ways to Instantly Repair Oversized Outlook PST 

We will discuss all the available manual fixes and the professional PST Compress or Split solutions. Also, we will study how to manage the corrupt PST files for free or with the dedicated solution without degrading the content or performance with or without Outlook. 

Method 1: Manual PST Size Reduction

First, to restore the complete Outlook functionality:

1. Check unnecessary items within your PST file. 
2. Remove any junk emails, items in trash, large attachments, and obsolete archives. 
3. Then, verify and remove duplicate emails in Outlook. 
4. Further, you must compact and split the oversized PSTs with built-in options. 

A) Compact PST File 

To remove the unused space from your PST file, MS Outlook has a built-in compression option. But it will only reduce file size and cannot repair corruption or handle severely damaged PSTs. Steps to fix large PST file are:

1. Open MS Outlook and from the File tab, go to Account Settings. 
2. Then, choose your Data Files and select the oversized PST. 
3. Further, click Settings and then Advanced. 
4. From there, tap Outlook Data File Settings and tap Compact Now. 
5. Wait until the process completes and the large PST files are compacted. 

B) Split & Archive Legacy Data 

The best way to prevent future issues is to split large PSTs and archive old ones, reducing the size of the main PST file. Follow these steps:

1. In MS Outlook, File tab, under Info, click Tools. 
2. Then, select Clean up Old Items, and a dialog opens. 
3. Further, choose Archive this folder and all subfolders. 
4. Pick a date range to archive emails for and select a destination. 
5. At last, save your old PST emails in a new .pst archive. 

If this doesn’t help, you can use the expert trusted SysInfo PST Split Tool to repair oversized Outlook PST by splitting them in one go. It allows division by Size, Folder, Date, and Sender’s ID with full precision and ensures faster Outlook performance, reduced corruption risks, and better mailbox management. It is safe and can manage single and multiple files simultaneously, keeping every folder item intact. 

C) Increase PST Size Limit 

Within modern Outlook interfaces (2010 or newer), anyone can modify Windows Registry files to increase PST size limits upto 100 GB. The steps to follow are:

1. Press Win+R to start the Run window, type regedit in it, and click OK or hit Enter. 
2. Then, locate Registry files from HKEY_CURRENT_USER\Software\Microsoft\Office\z. 0\Outlook\PST (where z.0 is 16.0 for Outlook 2016, 2019, 2021, and 365)
3. Next, right-click anywhere in the right pane and tap New. 
4. Select DWORD Value (32-bit) and give it a name as MaxLargePSTFileSize.
5. Furthermore, set it’s Base in Decimal and input the size in MB (51200 for 50 GB/102400 for 100 GB).
6. The PST file size will be reset to the newer value with more storage. 

Method 2: Repair Corrupt PST Files 

If you were unable to fix oversized PST, and it caused crashes or errors in the file, it must be damaged/corrupted by now. So, for the fix, Microsoft built-in Inbox Repair Tool is available, but it works best only on files of upto 2 GB. To use on large files, first compact or split them with the above-mentioned methods. To recover a corrupt PST, use these steps:

1. Initially, begin by closing the Microsoft Outlook application completely. 
2. Then, go to C:\Program Files (x86)\Microsoft Office\root\Office15/16 
3. There, locate ScanPST.exe and run the tool. Tap Browse from the dialog. 
4. Further, add the PST file that you want to repair and click Start. 
5. It will begin the scan and locate any errors. If found, hit Repair for the fix. 

You must note that this method will only deal with minor complexities and fixes. It cannot handle severe data corruption or damage. To ensure you can repair inaccessible or severely corrupted PST files, use SysInfo PST File Recovery Tool. It fixes all small and big structural inconsistencies, handles oversized PSTs, and recovers all with 100% accuracy without any data loss. The business-critical information is kept secure, and enterprises achieve great reliability. 

Method 3: IT-Based Repair Oversized Outlook PST 

Administrators managing large Outlook environments require a professional solution to fix large PSTs without corruption or data loss risks. Once you have recovered PST from damage or corruption, you can use SysInfo PST Compress and Compact Tool to reduce the large PST file size significantly with ease. It flawlessly shrinks the file, removes or extracts the large attachments, and maintains data integrity. With full support for both ANSI and UNICODE PSTs from all Outlook versions, it runs flexibly across all Windows and Mac OS. 

Steps to Fix Oversized PST Files 

1. Launch the SysInfo PST Compact Tool and choose Single/Multiple file. Tap Next. 
   
2. Then, with the Select File or Select Folder option, upload oversized PSTs and click Next. 
   
3. Further, preview the contents of your oversized PST files and select to compress. Hit Next. 
   
4. Afterward, choose how you want to compress the PST and use filters accordingly. 
   
5. Finally, select the Path to Save your compacted PST and tap Start Compression. 
   
   

How to Prevent Oversized PSTs in the Future?

• Keep older emails in separate PST archives regularly. 
• Monitor the growth of PST files and mailbox size at least quarterly. 
• Remove duplicates that consume your storage unnecessarily. 
• Compress PST data files periodically to reuse unused space. 
• Split very large PST files to achieve maximum size thresholds. 

Final Remarks 

Whether you are an individual, a professional, a business, or an enterprise, it is not very difficult to repair oversized Outlook PST files. The most common issue with PST files exceeding the size limit is MS Outlook corruption, mailbox inaccessibility, and related concerns. You can use the Inbox Repair Tool or PST Repair Tool to fix the corrupted PSTs initially. Once repaired, following the mentioned manual compact and split solutions, you can repair oversized PST. But for efficiency and long-term Outlook stability, it is suggested to use the SysInfo PST Compress and Compact Software.

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About The Author:

Simran Bhatia

Simran Bhatia is a technical content writer engaged in writing clear, concise, and SEO-optimized content. With a background in computer science and a passion for writing, I thrive to deliver complex technical content in simple layman terms.